How do i sell my 53 renault megane to someone without laughing???

Sometimes when i lock the car,the front passenger window goes down and won't go back up until it decides to,usually the next day, sometimes the day after.Also when i drive more than a couple of miles, all the windows steam up meaning i have to put the heaters on full whack just to allow me a little viewing hole through the windscreen.Oh and sometimes when started it makes a horrible grindy, gurgly sound,conks out then starts 2nd time round.Oh and the airbag light is on which renault want £300 to replace the rotary switch behind the steering wheel.Apart from the switch they said the car was fine! hahahaha!
We buy any car.com,We buy any car.com

Did i mention ive already had to replace the entire engine due to a new cambelt being fitted but mis-timed?
Go German,Go japenese,Go Anything but Renault!